How to Sprinkler Protect Open Baffle Ceiling?

8/14/2023

What are the requirements for sprinkler coverage for baffled ceilings?

In Florida we use the 2016 edition of NFPA 13. I know that the sprinklers have to be within 12 inches of ceiling for heat collection. The contractor says the pictures shown are correct.

I think they need to place a 12 by 12 above the baffle for heat collection?

I found 8.6.3.4 Minimum Distances Between Sprinklers.

8.6.3.4.1 Unless the requirements of 8.6.3.4.2, 8.6.3.4.3, or 8.6.3.4.4 are met, sprinklers shall be spaced not less than 6 ft (1.8 m) on center.
8.6.3.4.2 Sprinklers shall be permitted to be placed less than 6 ft (1.8 m) on center where the following conditions are satisfied: (1) Baffles shall be arranged to protect the actuating elements. (2) Baffles shall be of solid and rigid material that will stay in place before and during sprinkler operation. (3) Baffles shall be not less than 8 in. (200 mm) long and 6 in. (150 mm) high. (4) The tops of baffles shall extend between 2 in. and 3 in. (50 mm and 75 mm) above the deflectors of upright sprinklers. (5) The bottoms of baffles shall extend downward to a level at least even with the deflectors of pendent sprinklers.

If sprinklers are installed above and below the ceiling, a baffle needs to be installed around the lower sprinkler to avoid cold soldering. Cold soldering occurs when discharged water from the sprinkler above cools the thermal element of the sprinkler below, preventing or delaying its activation in the event of the fire. The required baffle will prevent that water from contacting the thermal element of the sprinkler, thus circumventing the possible issue.

Talked to some folks and we need the product paperwork as it may mention sprinkler coverage.

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7 Comments

Anthony

8/14/2023 07:33:34 am

It looks like you may be able to use 8.15.14* Open-Grid Ceilings rules. I'm not sure you have the 18'' above the grid ceiling however.

If you are unable to use the open grid rules you'll have to have a layer of sprinklers above the ceiling and one at the bottom of the obstruction. You should probably use intermediate level sprinklers with splash guards.

There are no apparatuses that aid in heat collection other than a ceiling.

Dave

8/14/2023 11:06:03 am

Another variation, sometimes for aeshtetic purposes these slatted ceiling systems recieve a black layer of insulation laying over the tops of the slats.

Glenn Berger

8/14/2023 08:11:13 am

Anthony has an acceptable approach stated above. If an issue still persists, then use obstructed construction rules.

Jesse

8/14/2023 10:01:49 am

I tell my young designers that at times it will seem architects are the bane of their existence. This is an example of why. I think Anthony is on the right track.

8/14/2023 10:56:52 am

Heat collectors / pie tins that us old f**ts were accustomed to were not addressed in NFPA #13 for a long while, but after being proved ineffective (downturned edges actually proved worse) they became prohibited in NFPA 13 several cycles ago.

8.5.4.1.4 (2016 ed.)
9.5.4.1.4 (2019 ed.)

There is always a new trend / fad that challenges us - cloud ceilings; slatted ceilings; lately, arrays of hanging vertical baffles; BAF's; soffit material that has favorable flame-spread but is not non or limited combustible by definition....

8/14/2023 11:02:37 am

...which I have to teach trainees were different in function and purpose from intermediate level shields

Janak Patel

8/16/2023 01:43:38 pm

It appears from the photograph that the sprinkler deflector is more than18" from the flat ceiling above. Since beams are so 'closely spaced' (not 7'-6" apart) it will be difficult to apply the Ceiling Pockets rule, NFPA 13 (2019), Section 10.2.9. Therefore, the situation does not comply with NFPA 13.

A heat collector, (12" x 12" or 12" diameter metal plate) at each sprinkler, would not work unless a fire is directly below the heat collector. It will take longer to descend/form a 'hot gas layer' to activate a sprinkler, i.e., a potential fire will be of a larger size. On the other hand, if there is no sufficient combustible load on the floor, sprinklers may never activate in an event of a fire. (A study has shown that heat collectors are 'not reliable' and Listed heat collectors are not available in market anymore.)

How to Sprinkler Protect Open Baffle Ceiling?

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